I want to add a 5Xmm 1.4-2.0 lens. Something just a little longer than the standard 50mm. I think I have it narrowed down to the Konica Hexanon 57mm 1.4, the Super Takumar 55mm 1.8, and the Helios 44 58mm f2. Just wondering if anyone could share their thoughts and recommendations. I'd like to keep it longer than 50mm but if there's one that stands out I'd like to hear about it as well. Thanks.